Radon transform in R

Question

I'm looking for an implementation of the radon transform in R. The only one I know of is in the package PET. However, it's not giving me the results I expect. I am using the example from the wikipedia page

require(png)
require(EBImage)
require(RCurl)
require(PET)

im <- readPNG( getBinaryURL( "http://upload.wikimedia.org/wikipedia/en/thumb/e/e5/Shepp_logan.png/170px-Shepp_logan.png" ) )[,,1]
rad = radon(im)$rData
# Normalize intensity values from 0-1
rad = normalize(rad)

display(t(im))
display(t(rad))

I get this image:

when I expect:

Am I using the parameters of the function incorrectly? I'm not too familiar with the details of radon transform

Answer 1

Look at the figures closer: both figures are the same, just shifted 90 degrees.
Recall the Radon transform just does line integrals across different degrees, it shouldn't matter whether it's transposed or not.
Also, the package PET is gone, and there does not seem to be another radon function in cran.
To install the latest PET you can do:

devtools::install_github('cran/PET')